According to University of Illinois professor May Berenbaum, men "have a deep-seated instinct to aim at targets" in the urinary sense. Logically, sticking a picture on the back of a urinal will cause men to aim for it like lemmings.

This is where the Thermal Urinal Fly comes in. These Japanese creations are thermally-sensitive, so as someone pees on one, the image of the Fly gradually disappears. And by offering up a target/game of sorts, there will theoretically be less mess (provided the sticker is strategically placed. You can get two for $10, though I'm not sure why anyone would want one for personal use. Do you have a urinal in your house? [White Rabbit Express via Book of Joe via Boing Boing]